Equipment for blow-out prevention



Dec, 5 1933. F1 w HlLD 1,938,019

EQUIPMENT FOR BLOW-OUT PREVENTION ,Fi led new. 15, l928' 4-Sheets-Sheet 1 I F. w. HlLD EQUIPMENT FOR-BLOW-OUT PREVENTION Filed Dec. is, 1928 4 Sheets-Sheet 3 Be s, 1933. w, H 1,938,019

' EQUIPMENT FOR BLOW-OUTFREVENTION I Filed Dec. 15,1928 4 shiisshet 4 \\\\\\\\\\\\\\\&

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Patented Dec. 5, i933 Frederic W. Hild, Los Angeles, Calif;

I Application December 15, 1928 Serial No. 326,208

Claims. (c1. ass-n rapidly than thatdue 'to the' quantity ejected.

My invention relates to the hydraulic system of drilling'used in the petroleum industry and appertains more particularly to equipment ior. preventing blow out of the fluids used and encountered in that system. 3

In this system a power 'conmionly rotates a hollow drill string consisting ofa swivel head, a square or fluted drill stem, a drill pipe and a bit.-

The swivel head is flexibly connected to a power driven hydraulic pressure pump, which forces mud fluid downward through the drill string, the mud discharging from the bit and returning upward outside the drill pipe and withinthelpipeor. well casing which is inserted in the bored hole and usually cemented to the sides thereof. Suitable conduit connects the well oi serious importance but may have disastrous casing with the mud pool which supplies the- .pump and the mud fluid is .thus circulated.

Among its several important .iunctions, the weight of the mud serves tocounteract'the underground fluid pressures due to gas or other fluids, so that with suitable mechanical means, the mud fluid may be utilized to control. the flow and the pressure of the subterranean fluids.

The hydrostatic pressure of the mud fluid in the-bored hole varies during drilling: on the one hand, if the mud circulation is maintained,

the pressure increases as the drill cuts downward; on the other hand, the head and the pressure' are subject to' diminution from several causes.-

When removing the drill string for-any reason:

the level of the mud' column lowers, whereupon the hydrostatic pressure lessens correspondingly.

This may be ofl'set by pumpin mud into the hole. Then, too, the mud density may diminish due to dilution when water strata having sumcient pressure are uncovered; this has the effect of lessening the hydrostatic pressureoi themud column. Furthermore, mud is 105 'by flltration into porous formations, or, when the drill opens an underground .cavity. Interruption of the mud circulation by the drilling crew, or because of defective equipment is only occasionally consequence in emergency. b

Obviously the hydrostatic pressure of the mud column should exceed the underground fluid pressures released by the drill, otherwise the mud will be forced upward together with the impelling fluid and both will escape through whatever openings. may be available in the; mud circulating system. Oncethe mud is thus started" upward, its counteracting force diminishes more driven rotary machine This is because the effective head of the mud column is caused, not alone by the actual quantity oi? mud in the hole, but in addition thereto by another quantity equivalent to that displaced by the submerged portion of the drill string. Thus as the impelling underground fluid pushes the mud out of the hole, the counteracting force rapidly lessens, andtheupward movement of both mud and fluid accelerates rapi ly, especially if an expansible medium such as gas be present.

It is commonly recognized that "mostot the gas and oil well blowouts which became conflagrations, were ignited by particles of stone or other substance that were rendered incandescent by friction with the well casing or the suspended ,drill' string while being ejected at tremendous speed by the escaping fluid. Y

Although high underground pressures have been encountered at comparatively shallow depths, it is manifest that the greater depths to whichwells must be bored, mean higher pressures which unless adequately controlled, increase the hazard, to persons and property. The suddenness, the rapidity and the other exigencies involved, demand automatic, quick acting control apparatus quite beyond mere reliance upon manual effort of the workmen. -My invention provides methods andv equipment which success-- in simple and eflectlvemanner.

Among the-objects ol my invention are to provide methods of-controlling the ejection of the mud and the 'impelling fluid by utilizing the new of the mud from the bored hole to eflect timelyand suitable closure of the mud discharge paths. 1

It an, object 01 my invention to provide in each of the several paths through which the mud and the underground fluid may be ejected-a device which shall automatically eflect closure of each path when the pressure of the underground fluid begins to exceed that of the mud fluid.

Thusan objectof my invention is to provide a self-acting discharge valve, which shall permit the-free circulation and discharge of the mud fluid during normal drilling but which shall automatically close when the flow of the mud fluid through the valve exceeds a predetermined rate. Another object of my invention is to provide a control device which shall automatically close the said valve whenthe mud fluid level in the bored 110 .iullymeet' the conditions and prevent'blowouts hole falls below or rises above predetermined limits.

Another object of my invention is to provide buoyant bushings on the drill string floatable in the mud fluid, and actuated by the mud fluid to effect closure of the upper end of the well casing in accordance with the excess of the underground fluid pressure.

Still another object is to'provide a multiple oasing valve secured to the well casing which without change of its parts may engage drill strings of different diameters and thereby effect closure of the well casing. Further objects are to effect closure by such a valve either with or without the drill string or the rotary machine; also to effect such closure at the drill stem, or at the drill pipe,

or at a tool joint or at a rotatable member of the rotary machine such as the drive bushing.

Still another object of my invention is to provide a drill stem bearing bushing for effecting 'closure of the well casing which shall 'be selfnection by means of a valve rigidly secured to the rotary machine and a slip joint slidably connecting said valve with the well casing. Further objects of my invention are to provide a rotary drilling machine with a drive bushing adapted to be rotatably engaged by said valve so as to effect closure for preventing the ejection of fluid from the well casing, and also to'prevent upward displacement of the drive bushing, thereby relieving thebearings and gears from the stresses and strains due to upward forces encountered during the drilling operations.

It is an object of my invention to provide equipment for fluid control and blowout prevention which may be interchangeably used with rotary drilling or cable tool drilling.

Other objects and advantages of my invention will be apparent from the following detaileddescription taken in conjunction with the drawings.

Figure 1 shows in vertical elevation and part section the application of my invention. Here are seen the rotary machine engaging the drill string AiO which extends through a multiple casing valve and the well casing; also a tandem discharge valve for the mud fluid, a motor for the tandem valve, a fluid level box and the pump and the connections for the mud circulation.

Figure 2 is an enlarged view in vertical section of the multiple casing valve and the floating bushlngs on the drill string. 1 i

Figure 3 is a horizontal section taken on the line 3-3 of Figure 2.

Figure 4 is a horizontal section taken on the line 4-4 of Figure 1, through the back pressure valve in the drill string.

Figure 5 is a horizontal section of the multiple casing valve taken on the line 55 of- Figure 2.

Figure 6 is a vertical section of the tandem' dischargevalve.

Figure '7 is an end view of the tandem valv shown in Figure 6. V

Figure 8 shows in part vertical section the drive bushing of a rotary machine engaged by the multiple casing valve.

contacts.

Figure 9 shows in part vertical section, the drill pipe engaged by the multiple casing valve; also the latter secured to the rotary machine and to a slip joint which'connects with the casing.

Figure 10 shows a self aligning, self centering drill stem bearing seated on and engaged by the multiple casing valve.

Figure 11 is a horizontal view in 'part section taken on the line 11-11 of Figure 10.

Figure 12 is a part sectional elevation showing the application of my invention to cable tools.

Referring now to Figures 1 and 2, the rotary machine 1 engages the hollow drill string 2 which comprises the swivel head 3, the drill stem 4, the drill pipe 5, the tool joints 6, the bit 7 and the back pressure valve 8. The pump 9 draws mud from the supply pool 10 through the suction pipe 11 and forces the fluid through flexible hose- 12 into swivel head 3 and down through the hollow drill string 2 emerging therefrom at the holes 13 in bit 7. A valve 14 atthe pump controls the fluid flow through the hose 12. 7

One or more strings of well casing are inserted into thebored hole 15 such as the outer string 16, a second string 1'7 and a third string 18. Upon a suitable base or foundation 19 is mounted a casing clamp 20 which provides common support for suspending the several casings. The outer string 16 is threaded directly into the clamp 20.

Casing 17 is threaded into collar 21 which rests upon the annular projection 22 of the casing clamp 20, while casing 18 is threaded into collar 23 which rests upon collar 21. Thus the casing clamp and the foundation support the casings against the downward pull due to their weight, and the combined casings oppose upward force which may be transmitted by the casing clamp.

Secured to the top of casing clamp 20 is the multiple casing valve 24 through which the drill string 2 may extend and be engaged by the casing valve as more particularly described hereinafter. Into the side of easing valve 24 below its gate members, is connected a pipe 26 to conduct fluid from the well casing to the tandem discharge valve 25 which is connected to the pipe 26. The by-pass valve 26a connected to the pipe 26 permits discharge of the fluid when the tandem valve 25 is closed.

Two other openings in the casing valve 24, below that for pipe 26, are provided for connection with two other pipes one of which namely,

pipe 27, connects with the pump 9 at the plain valve 28 for conducting fluid from the pump into the well casing. The other pipe 29 connects the casing valve 24 with the fluid level box 30.

The fluid level box operates a double throw switch 31 which controls the electrical circuits from the power means 32 to the motor 33. This motor, acting through a suitable speed reducer 34, operates to close the tandem discharge valve 25 when the switch 31 is thrown to either of its The tandem valve upon starting to close, actuates switch 35 which closes the electrical circuits to energize a suitable signal device 36 which may be audible or visual or both.

Considering now the casing valve 24 and re-- ferring also to Figure 5, the body 37 has a vertical cylindrical opening 38 extending through the body, the axis of which lies in the drilling axis which is common to the rotary machine, the drill string, the casing clamp and the well casing. In the body 37, at right angles to the opening 38, are bored two cylindrical valve seats 39 and 40 for receiving two rotary valve gates il and 42 respectively, which may bemounted on the shafts to operate thereby causing the tandem valve to close.

The simple, automatic operation of the system described is evident. During normal drilling,

the mud fluid after being forced down the drill string 2, discharges from the bit 7 at the bottom of the hole, and flows upward between the drill string and the inner well casing through the casing clamp 20, to the lateral openings in the cas ing valve 24, into which are connected the pipes 27, 29 and 26. The valve 28in the pipe 27 is closed except as hereinafter stated. The fluid rises in pipe 2'7 and in the fluid level box 30 to the common level of normal flow through pipe 26 and the tandem valve 25. p

The buoyant bushing 60 which normally is on the square part of the drill stem 4, will rotate with the latter in the mud fluid, but the bushing because of its buoyancy, will float on the fluid as the drill stem moves up or down. The bushing 64in which the drill pipe 5 may rotate, is submerged but because of its buoyancy the bushing 64 will bear against the tool joint 6 above it.

likewise, the bushing will rise.

'drill string would oppose its further rise.

' When the bit releases underground fluid'having sufficient pressure to overcome the weight of the mud column in the hole,-the mud fluid level will rise in the casing valve 24, in the pipe 26, in the tandem valve 25 and in the fluid level box 30; At the same time the mud flow through pipe 26 and the tandem valve 25 will increase and thereupon, the tandem valve will be closed by the flowing mud and the signal device 36 will warn the drilling crew as previously explained. But one outlet, the

casing valve 24 remains available for the escape of the mud fluid, which rising in the valve, carries with it the bushing 60 and forces the latter into the seat formed by the conical openings 56 1 and 5'7 of the rotary gates 42 and 41j'respectively;

whereupon closure is effected. This is indicated by the broken line 88 in Figure 2.

Warned by the signal, the driller will have ample notice to begin increasing the density-of the mud fluid and to either stop the rotary machine or else to hoist the drill string until the round portion 63 of the drill stem 4, is within the bushing 60, thereby enabling rotation of the drill string, while circulating the mud fluid through the by-pass valve 26a. 11, instead of encountering high underground fluid pressure, the bit had opened a cavity into which the mud fluid could flow, and substantially lessen the level .of the mud column in the casing,--then the float 84 in the fluid level box 30, responding to the lowered level, would cause the switch 31 to close thereby energizing motor 33 which thereupon would close the tandem valve 25 and operate the signaldevice 36, warning the driller to stop drilling andto replenish themud column.

The lowered fluid level ings 60 and 64 to descend to the next. tool joint below each respectively. Should the driller persist in drilling deeper with inadequate mud column and release excessive underground fluid pressure-then the resultant rise of fluid would be impeded. flrst by bushing 64 and then by bushing 60. The bushing 64 would rise to the tool joint above it and then the weight of the bushing 60- would be forced into its seat in casing valve'24 whereupon the outlets wouldjbe closed. if the pressure be sufficient to lift the drill string, thelatter could move upward only. the short distance from the tool joint to the I slip joint 89.

would allow the bushbushing seated in the casing valve; then the combined weight and resistance of the several. casings and the drill-string would oppose the upward fluid pressure and further upward movement of the drill string.

When removing the drill string to change bits 1 or the like, during a condition of near equilibrium of the opposing fluidsin the hole, the first lowering of the 'fluid level due to-removal of the drill stem or -a length of drill pipe will cause the tandem valve to close, as before explained. The

driller will replenish the mud column by pumping mud fluid through pipe 27 into the well casing; and when the bushing 64 is removed, the

' driller may rotate the casing valve gates until the openings 52, 53, 54 and 55 have their axes in the common drilling axis.

I In this position, which is illustrated in Figure 9,-upward movement of the drill pipe is opposed at the tool Figures 8 and 9 show the casing valve 24 secured directly to the rotary machine 1 and secured flexibly to the well casing by means of The slip joint hasannular projection which fits. slidably'on casing 16. A collar 91 threaded on to the casing bears against packing 92 which is within-the slip joint and rest- "ing onprojection 90. Thus the rotary machine and the casing valve may move downward to a limited extent but upward .displacement is prevented by the slip joint and the well casing.

The rotary machine ofv Figure 9 may be such as described in my aforesaid co-pending application Serial No. 312,887, but in Figure 8, the drive .bushing 93 of the rotarymachine 1 has an extension 94 with an overhanging annular. mud deflector 95. The extension 94 below the shoulder of the mud deflector 95 is journaled in split bearings 96 which are held in place by sleeve 97 surrounding the split bearings and by the washer 98, and the two jam nuts 99 and 100 on thev threaded lowerend of extension 94. The sleeve 97 has an annular extension 101 surrounding the washer and jam nuts and forming the shoulder 102. The mud deflector 95'serves to deflect downward moving mud or other foreign substances from the split bearings. 96 and sleeve 97, while the sleeve 97 serves a like purpose for the bearings, the washer and the jam nuts. Lubricant may be supplied to the bearings and the journal surface of the drive bushing 93 by grease gun pressure applied to a suitable duct from the top of the drive bushing.

The sleeve 97 is held firmlyby the casing valve 24 so as to prevent its rotation and upward displacement. This is accomplished by rotating the valve gates until their openings 103 and 105 in gate 41, and 104 and 106 in gate 42 have their axes in common drilling axis.' In this position, the valve gates 41 and 42 closely fit the outer cylindrical surfaces of the sleeve 97 and its extension 101 and when-the drill stem 4 is in the drive bushing 93, closure of the casing valve 24 is effected and the rotary machine drivebushing is rotatably. secured by the casing valve 24 so as to prevent its upward displacement.

"Frequently more than one size (diameter) of drill pipe and tool joint areused in boring the same hole.. The casing valve 24 provides for this .by the openings 107 and 109 in valve gate 41 50 of the bearing'in the blocks enable the drill stem openings 52,53, 54 and 55 previously described and are for use with anothersize drill pipe and toolioint. 4

The drill istem' 'bearing 111 comprises the journal bushing 112 through which extends axially a square hole slidably fitting the squaredrill stem 4. The lower end of thebushing is larger in diameter than the upper portion with which it forms the shoulder 113. .The bushing .112 actsas a journal for the drill stem and rotatesin the self-aligning radial and thrust bearing 114, the

thrust being at the shoulder 113. The upper'end .of bushing 112 is threaded to receive mud -de-.

" flector 115 and jam nuts 116; the mud deflector in the slots 125 formed by the circular brackets 4o tapered faces forming a breech lock, so that as the casing valve 24. Y The lower portion 120 of the .block 118 projects downward-into the openings 121 and 12201 the valve gates 41 and 42 respectively which lock the block 118 firmly rotation and axial displacement.

The block 117 has-radially projecting tongue 123, the upper faces 124 of which are at a com-; paratively small angle 'with a plane perpendicular to the common drilling axis. When lowering the assembled drill stem bushing 111 into the casing valve, the tongues 123 are first inserted a ainst 126 on the body 87 of the casing valve 24. Then the block 117 is rotated a. few degrees thereby moving the tongues 123 into the grooves 127 which are extensions of the slots 125. 'The"un-' derfaces of the grooves 127 have-the same tapered angular relationship as the faces 124- of tongues 123, the arrangement of the slots grooves and the block 117 is rotated it is forced downward thereby applying pressure to the spherical portion of bearing 114 which in turn transmits the from the lateral openingconnected with pipe 26.

pressure to the lower block 118; the result being flrm, tight, secure seating of the two blocks and the" spherical hearing as among themselves, and the drill stem bearing as a whole in the upper body portion of the casing valve 24. Lateral clearance betweenthe circular brackets 126-and the blocks 117 .and' 118 together with "thespherical seating 7.

bearing 111 to be self. aligning and self centering with respect to the drilling axis. When the drill stem bearing 111 is flrmly seated and secured in the casing valve 24'as described, the casing'valve is closed to fluid flow which must then discharge In Figure 12. the wire line 128 passes through a guide packing-bushing 129 and may be secured to a string of cable tools130 or to a bailer when removing the mud fluid. The gates 41 and 42 of the casing valve 24 engage the bushing'l-zaiand thereby effect closure of the valve and of the casing outlet. The opening 131 in gate 41 and the opening 132 in gate 42 may be generated in the following manner: consider a-cone shaped end in the valve center which is the point of tan-.

gencyofthe'drillingaxisandthetwogateaand 'its base below, rotating -in the drilling axis. 'I'hen by ceding the cutter upwardjthroughthe and simultaneouslylrotatlng the two gates such that gate '42. moves clockwise.

gradually increasing in diameter from zero (valve closure) to the maximum valve opening 50- -51 formed by the gates 42 and 41 respectivelyas previously explained. It will. be noted that fluid flow through the. casing valve 24 and the tandem valve 25 is always in the one direction 'and'the valves function to close automatically with the same direction of pressure and :flow. The back .pressure valve il'in the tool joint 6 is unaffected by increase or decrease of fluid flow or pressure'in the normal (11: 1 rection down the drill string; but functions to close automatically when the pressure and theflow are reversed. a Although I have described several specific bodiments of my invention, it, will be obvious-rte those skilled in the art, that various modifications may be made inthe details of constructiomthe general arrangement,- the association of the sev eral co-operating 'parts and the application "of my invention without departing from the spirit thereof or the principles herein set forth.

I claim as my invention: 3

1 In. equipment for preventing blow out of fluid from -a well, the combination of: well cas-. ing, a casing valve connected thereto; a drill string extending through said valve, and means slidable on said drill string concentrically interposed' between said string and said valve for controlling the valve opening.

.2. In blow out prevention equipment, the combinationof; a casing. valve, and means concen-' trically disposed within said valve comprising a 'revolvable member slidable ona rotary drill stem for controlling said valve. 110

.3.A control head for well casing, having an opening; and a-buoyant member floatable in mudv fluid, and 'slidable. on a drill string for closing said opening. I a

nected in-series and counterbalanced for normally open valve position, one of said gates being positioned to initiate the closing ofthe valve by the other gate, either upon increase 'of the fluid flowing through the valves, or upon rise of the 120 level of said fluid.

5. A casinghead having an outlet-for conduct ing fluid froma well, and a member floatable in said fluid for engaging said outlet when the level I 128 6. A. casinghead, a plurality of gate members adjustable to form anyof 'a pluralityv of different configurations of axial openings for conductingfluid from a well; and supported on the casinghead, and a member fldatable in said fluid and conforming with at least one of said conflguraq tions to close the outlet from the well. J

7. In equipment of the character described. well casing, a'valve connected thereto, a drill string extending through the valve, and a floatable closure for the valve slidable on the string, for controlling .the valve opening.

8. A casinghead having a lateral discharge opening, a weir leading from said opening, a closure for the opening, agate for the weir, and a 146 connection between the closure andthe gate.

"9. A 'casinghad having a lateral discharg opening,a closure forsaid opening, and means responsive to a variation 'of liquid; level beyond definite high andlow points for moving said clo- .sure to close the opening.

10. Acasinghe'ad havinga lateral discharge ,MM. a weir leading-from saidopening-a clo.- sum for the opening, agate-for the-weir. and

wherebyafn cfliquidin theweh',

' 4. An automatic valve having two gates con-,-

it I

' acting on the gate, responsive to an increased means to closed position.

' rate 01 flow or liquid closes the valve.

11. A'casinghead having a lateral discharge openingia weir leading from said opening, a closure for the opening, a gate for the weir, a connection between the closure and the gate, means urging the valve to open position and through the intermediary of the connection, also urging the gate out of the path of the liquid passing through the weir, and a motor for moving the valve to close the gate.

12. .In a well drilling system which circulates mud fluid or its equivalent to counteract the pressure of underground fluid, a weir into which the fluid discharges, and a valve mechanism cooperating with the weir to stop the flow when the fluid level in the weir reaches a definite level.

13. A casinghead for a well, said casinghead having an outlet, means for circulating mud fluidor its equivalent in the well, and means for closing theoutlet, said closing means including a member actuated by a variation in the rate of fluid flow from a desired rate for moving the closing 14.. A casinghead having an outlet, a closure ior the outlet, and means actuated by an increase in the rate of flow of fluid circulating in the well,

above a desired maximum rate, for initiating the operation of the closure.

15. A casinghead having an outlet for con- I ducting fluid from a well, a member floatable, in

said fluid for engaging said outlet when the level rises, and a guide extending through said member for accurately positioning said member with respect to the opening.

16. A casinghead'having a lateral and an axial outletsffor controlling fluid flow from well cas ing, closures for both of said outlets, andmeans the pipe or the stem.

responsive to a rise in level of the fluid for actuating one of said closures to close the corresponding outlet, the other closure incorporating means whereby the operation of, said one closure,

' causes the other closure to close its outlet.

17. A casingheadhaving alateral and an axial outlets for controlling fluid flow from well casing, closures for both or said outlets, and means responsive to abnormal conditions in the flow of the fluid, for actuating one of said closures to close the corresponding outlet, the other closure incorporating means whereby the operation of vsaid one closure, causes the otherclosure to-close its outlet.

18. A control head for well casing, including a housing, adjustable means in said housing for .controlling an axial opening'through said housing, and means for adjusting said means so that it may optionally operate to close the openingin cooperation with either a round drill pipe or a bushing surrounding an angular faced drill stem,

or for closing said outlet in the absence of either 19. A control head for well casing, comprising means forming a taper bored seat converging upwardly'from the well casing and forming an axial opening through which a drill string is adapted to extend, and a correspondingly tapered pecker slidable with respect to the drill 

